What gives SE the legal right, under the CC-BY-SA license, to modify user profiles without indicating that the content has changed?

Question

The Terms of Service clearly indicated that all content that you provide to SO Inc is licensed under CC-BY-SA, and that would include your About Me section of your user profile, which SO Inc is actively modifying, without indication, to remove links to a community fundraiser.

You agree that any and all content, including without limitation any and all text, graphics, logos, tools, photographs, images, illustrations, software or source code, audio and video, animations, and product feedback (collectively, “Content”) that you provide to the public Network (collectively, “Subscriber Content”), is perpetually and irrevocably licensed to Stack Overflow on a worldwide, royalty-free, non-exclusive basis pursuant to Creative Commons licensing terms (CC-BY-SA).

Unlike previous versions, there's no exceptions for your content based on the type of content, or whether or not it gets populated with the the public API.

Currently, SO Inc insists that all content is now CC-BY-SA 4.0, which means that all modifications must be indicated.

FAQ version:

In the 4.0 license suite, licensees are required to indicate if they made modifications to the licensed material. This obligation applies whether or not the modifications produced adapted material. As with all other attribution and marking requirements, this may be done in a manner reasonable to the means, medium, and context. For example, "This section is an excerpt of the original." For trivial modifications, such as correcting spelling errors, it may be reasonable to omit the notice.

Full legal text:

Section 3 – License Conditions.
Your exercise of the Licensed Rights is expressly made subject to the following conditions.  
 a.Attribution.  
  1. If You Share the Licensed Material (including in modified form), You must:  
   A. retain the following if it is supplied by the Licensor with the Licensed Material:  
    i. identification of the creator(s) of the Licensed Material and any others designated to receive attribution, in any reasonable manner requested by the Licensor (including by pseudonym if designated);  
    ii. a copyright notice;  
    iii. a notice that refers to this Public License;  
    iv. a notice that refers to the disclaimer of warranties;  
    v. a URI or hyperlink to the Licensed Material to the extent reasonably practicable;  
   B. indicate if You modified the Licensed Material and retain an indication of any previous modifications; and  
   C. indicate the Licensed Material is licensed under this Public License, and include the text of, or the URI or hyperlink to, this Public License.  
  2. You may satisfy the conditions in Section 3(a)(1) in any reasonable manner based on the medium, means, and context in which You Share the Licensed Material. For example, it may be reasonable to satisfy the conditions by providing a URI or hyperlink to a resource that includes the required information.  
  3. If requested by the Licensor, You must remove any of the information required by Section 3(a)(1)(A) to the extent reasonably practicable.

So where does Stack Overflow get the right to modify licensed content without indicating changes?

Answer 1

The question is essentially about whether or not something is legal, and hasn't got an answer in over 13 months, which I think would not have been the case had the OP tried this.

Summary of the matter

The title of this question, and the first bird's eye look at the entire question page left me still wondering what this was about. I had to open a link in the question to find out that: this is all about a link to a fundraiser, which was removed (by SE) from people's profiles without telling them.

The question and answer to which the link points, makes no mention of what fundraiser this was, but I'm certain it was the "GoFundMonica" fundraiser which was made because of this: Monica's situation continues unresolved. Is SE hoping the problem just goes away?

My opinion on the matter

The OP and the ~150 people that upvoted this question will not like what I say below about the legal perspective, so I just want to say that I personally supported Monica through and through and did and still do support anyone that posted a link in their profile to support her. But the question is not "do we like what SE did?" it is "were they on the right side of the law?", and it seems the OP was hoping that the answer is "no", but the answer is (unfortunately for the OP) "yes".

Implications of CC-BY-SA

CC-BY-SA is the name of a Creative Commons license, the "BY" means "by attribution" meaning essentially that the licensee (Stack Exchange Inc.) can modify or distribute the original content only if they give attribution to the original author, and the "SA" means "share-alike" which just means that when copies of the work is shared it must be shared with a license that is the same (or not more restrictive) than the original license.

Do we have a legal right to know when a link to a fundraiser is removed?

The CC-BY-SA license is a copyright licence. This is the definition of copyright from Wikipedia:

"Copyright is a type of intellectual property that gives its owner the exclusive right to make copies of a creative work, usually for a limited time."

Notice the word "creative". Sure you can argue that the link to the fundraiser was "creative", but let's look at what legally qualifies as "creative":

"Copyright may apply to a wide range of creative, intellectual, or artistic forms, or "works". Specifics vary by jurisdiction, but these can include poems, theses, fictional characters, plays and other literary works, motion pictures, choreography, musical compositions, sound recordings, paintings, drawings, sculptures, photographs, computer software, radio and television broadcasts, and industrial designs."

Sure, this is not a "complete" list, but I doubt there's a judge in the world that would stretch the word "creative" to include a link to a fundraiser. Therefore, links to fundraisers are not protected by CC-BY-SA or any copyright license.

How do I know this?

I used to (sometimes) hate when people forwarded my emails without my permission. I began putting a copyright notice below my emails, saying that I own the copyright to what I write (which does turn out to be true) and that the receiver doesn't by default have permission to redistribute (forward) the email without asking me. Legally, this is enough for a copyright to be legally binding:

"In all countries where the Berne Convention standards apply, copyright is automatic, and need not be obtained through official registration with any government office. Once an idea has been reduced to tangible form, for example by securing it in a fixed medium (such as a drawing, sheet music, photograph, a videotape, or a computer file), the copyright holder is entitled to enforce his or her exclusive rights."

but only if the work is "eligible" to be protected by copyright (see the section immediately before this one).

Conclusion

CC-BY-SA is there to protect the creative work that volunteers do when writing things like questions, answers, and every tag wiki. But a link to a fundraiser is not eligible for copyright, and therefore not protected by CC-BY-SA, and therefore the OP's argument that CC-BY-SA requires authors to be informed when their work protected by copyright is changed, would not likely hold water in any court of law in the world.

This does not mean that it was nice for SE to remove people's links to fundraisers without telling them. At the same time, if you're reading this, you probably like participating in SE and might appreciate that if a fundraiser (not necessarily the specific one in question here!) to sue SE is successful enough, SE could find themselves owing millions of dollars to someone, which they can't afford, which might mean the end of SE. Still I think it would not have harmed SE to have told users that they edited the profiles, but they didn't legally have to, and I don't see what difference that would have made for the users that were trying to raise money: the links would go down whether or not the users were told.